Greenlee long drill/tap bits expand the performance of this popular product line. Drill, tap and countersink up to 4X"s faster than traditional tapping methods. Tap up to 1/2-inch thick mild steel, copper, brass and aluminum. Long drill/tap bits are a great addition to our standard length drill/tap bits which can tap up to 1/8-inch thick material using 6-32 to 1/4-20 standard threads and M3 to M10 metric threads.